It is not always preferable to plough an area of land in a series of straight, and substantially parallel lines. An example of this is where the boundary of the area is not in a regular shape, such as a square or rectangle, wherein ploughing the area in straight lines results in less overall area being sowed with crops than would be the case if the area was ploughed in a series of concentric paths that follow the boundary of the area.
Another example of where ploughing in parallel straight lines is not preferable is where a central irrigation point delivers irrigant in a radially outward direction. If the area is ploughed in parallel straight lines a uniform, volume of irrigant may not be received throughout the area.
Finally, where the area to be ploughed is sloped, it is preferable to plough along lines of uniform elevation, which usually do not follow a straight path.
Computer guided agricultural vehicles are known in the prior art. For example in the international patent application PCT/AU99/00930 (WO 00/24239) to the same applicant, there is described a computer guided agricultural vehicle which follows a series of parallel straight lines. The current guidance systems generally operate by specifying initial path data to the system, that is usually a straight line, with the system generating a subsequent path for the vehicle to follow using the specified path data. The vehicle is then guided along the paths by the guidance system.
Current computer guidance systems for agricultural vehicles however have not been particularly successful in generating guidance paths other than straight lines that can be easily followed by an agricultural vehicle. It has even been found that it is necessary for a vehicle to be stopped and reversed in order to follow the path that has been generated by the guidance system. Having to stop and reverse the vehicle is inconvenient because the implements used are usually towed and cannot be raised hydraulically. It is also a waste of resources such as fuel, particularly where broad acre farming is involved.
It is an object of the present invention to provide a guidance which allows a vehicle to be continually guided along a generated path without having to stop and reverse the vehicle.